Larger solar collector installations usually include an array of solar collector devices. Such systems can be used in conjunction with photovoltaic modules, thermal solar collector devices as well as concentrators for concentrating solar energy onto photovoltaic devices or thermal solar collection devices.
Some of these solar collector installations include hardware for automatically adjusting the position of the collector devices to track the sun as it moves across the sky. This tracking movement can be accomplished in a number of different ways. Some systems use a single axis tracking system in which the collector devices pivot about a single axis. Such single axis type tracking systems often include a drive shaft or “torque tube” which defines a single pivot axis.
Further, in some of these systems, the torque tube can be used to both support the solar collector devices and transmit the torque used for adjusting the position of the solar collecting devices. In order to reduce friction which would resist the pivoting movement of the torque tube, some systems include bearings for supporting the torque tube above the ground and so as to be pivotable about the pivot axis.
Because the torque tubes pivot through a limited range of rotation about the axis, conventional roller bearings are not necessary for such applications. Rather, roller bearings would present an unnecessarily large expense. Thus, some sun tracking solar systems include other types of bearings.